1. 4. Quality Control of Composition, Microstructure and properties of refractories

12. . Cold- and hot- modulus of rupture, (CMOR and HMOR, kg/cm2, N/mm2 (MPa): CMOR or HMOR are the capability of a rectangular bar sample to resist breaking by bending stress at room temperature or at high temperatures, respectively. They are calculated according the following equation: CMOR or HMOR. = x , [kg/cm 2 , N/mm 2 (MPa)], Where: F = Stress at which the sample is broken, L = Sample length, W = Sample width, R = Sample thickness Rate of loading: - 1.5 kg / cm 2 / sec … For dense Refractories, - 0.5 kg / cm 2 / sec … For lightweight Refractories.

16. Figure 1: Reversible Linear Thermal Expansion of Some Refractories

22. Figure 2: Thermal Conductivity Curves of Some Refractories

30. Figure 3: RUL Curves of Some Refractories

34. Figure 4: EPMA-Line Scans Showing the Changes Occurred in the Chemical & Phase Composition and Densification Parameters of a Magnesia-Chrome Lining / Cement-Clinker Interface in the Clinkering Zone.

35. Specific Gravity & Prosity using Pycnometer

36. Specific Gravity using Pycnometer W 1 (weight of Pycnometer ) W 2 (weight of Pycnometer + Sample ) W 4 (wt of Pycnometer+ Sample+ water ) W 3 (wt of Pycnometer+ Sample+kerosene )

37. Apparent Porosity D (Dry weight of specimen ) S (Suspended weight ) W (Saturated Weight ) True porosity = = [( ρ – B ) / ρ ]100 Apparent Porosity

39. Solved example for : Density – and Porosity- calculations

40. Silicon carbide particles are compacted and fired at a high temperature to produce a strong ceramic shape. The specific gravity of SiC is 3.2 g/cm 3 . The ceramic shape subsequently is weighed when dry (360 g), after soaking in water (385 g), and while suspended in water (224 g). Calculate the apparent porosity, the true porosity, and the fraction of the pore volume that is closed. Example 14.4 SOLUTION

41. Example 14.4 SOLUTION (Continued) The closed-pore percentage is the true porosity minus the apparent porosity, or 30 - 15.5 = 14.5%. Thus: